Separate Start Unknown


Connie had some marbles. She gave 5 to Juan. Now she has 8 marbles left. How many marbles did Connie have to start with?



_-5=8

Strategy- Trial and Error

Explanation of Strategy
We took a handful of units to represent "some". Then we gave 5 to Juan and moved the units away from the pile. We then counted out 8 for Connie and removed any excess units. Last, we joined the units from Juan and Connie to get 13.

Counting Up To
Start with "5" and count up eight 6 7 8 9 10 11 12 13
5+8=_



Explanation of Strategy
We put the number 5 in our head and counted up 8 times to arrive at the number 13.

Facts
5+5=10 10+3=13



Explanation of Strategy
We started with 5 and joined it with 5 more from the 8. We then added the 3 left over to get to the answer 13.